import sys
input = sys.stdin.readline
MOD = 998244353
N = int(input())
S = input().strip()
dp = [[0 for _ in range(3)] for _ in range(N+1)]
dp[0][0] = 1
for i in range(N):
    for j in range(3):
        if dp[i][j]==0:
            continue
        if S[i]=="L":
            if j!=1:
                dp[i+1][0] += dp[i][j]
                dp[i+1][0] %= MOD
        elif S[i]=="R":
            dp[i+1][1] += dp[i][j]
            dp[i+1][1] %= MOD
        elif S[i]=="U":
            dp[i+1][2] += dp[i][j]
            dp[i+1][2] %= MOD
        else:
            if j!=1:
                dp[i+1][0] += dp[i][j]
                dp[i+1][0] %= MOD
            dp[i+1][1] += dp[i][j]
            dp[i+1][1] %= MOD
            dp[i+1][2] += dp[i][j]
            dp[i+1][2] %= MOD
ans = sum(dp[N])%MOD
print(ans)